Granulomatous lesions in lymph nodes of slaughter pigs bacteriologically negative for Mycobacterium avium subsp. avium and positive for Rhodococcus equi

The prevalence of granulomatous lesions in lymph nodes of pigs was studied. From January till August 2004 in two slaughterhouses in The Netherlands 2,116,536 pigs were examined for the presence of granulomatous lesions in the sub-maxillary lymph nodes. In 15,900 (0.75%) of these pigs, lesions could be detected. Nine farms with the highest incidence of lesions were selected for a more detailed pathological and bacteriological examination. On these farms, the prevalence of lesions in sub-maxillary lymph nodes ranged from 2.3 to 5.7% with a mean of 3.0%. From 1276 pigs that were sampled, 98 (7.7%) displayed granulomatous lesions in the sub-maxillary lymph nodes and one (0.1%) pig showed lesions in its mesenteric lymph node. Mycobacterium avium subsp. avium (MAA) could not be isolated from the lymph nodes of the 99 pigs with lesions and from a selection of lymph nodes (n = 61) of pigs without lesions. Rhodococcus equi was isolated from 44 out of 98 (44.9%) of the sub-maxillary lymph nodes with granulomatous lesions and from two mesenteric lymph nodes without lesions. A comparison of former studies and the current results indicate that the prevalence of MAA infections in slaughter pigs has strongly decreased over the last decade, whereas R. equi is highly prevalent. The high incidence of granulomatous lesions associated with the bacteriological presence of R. equi could be considered as a serious cause of misdiagnosis of MAA infections in cases where meat inspection is carried out by inspection for granulomatous changes of lymph nodes only.     

Biodegradation of methylthio-s-triazines by Rhodococcus sp. strain FJ1117YT, and production of the corresponding methylsulfinyl, methylsulfonyl and hydroxy analogues

A novel bacterial strain FJ1117YT was isolated from an enrichment culture with the herbicide simetryn. The isolate was capable of degrading the herbicide supplied as the sole sulfur source in an aquatic batch culture. The strain FJ1117YT was identified as that belonging to Rhodococcus sp. on the basis of comparative morphology, physiological characteristics and comparison of the 16S rRNA gene sequence. The biodegradation pathway of simetryn was established by isolating the methylsulfinyl analogue as the first metabolite and by identification of the methylsulfonyl intermediate and the hydroxy analogue by liquid chromatography-mass spectrometry (LC-MS) and/or nuclear magnetic resonance (NMR) analysis. The results indicate that the methylthio group was progressively oxidised and hydrolysed by the strain FJ1117YT. The same strain is also able to metabolise other methylthio-s-triazines such as ametryn, desmetryn, dimethametryn and prometryn through similar pathways.     

Cortical Osteitis of The Humeral Diaphysis Caused by Rhodococcus Equi

Infection with Rhodococcus equi is a common cause of pneumonia in foals. Extrapulmonary manifestations occur, including gastrointestinal disease such as enterocolitis, musculoskeletal disease such as osteomyelitis, as well as other aberrant regions of abscess. Osteomyelitis predominately occurs in the metaphyseal or epiphyseal regions of long bones because of low-pressure blood flow through the sinusoids of these regions of the bone. In this report, a case of cortical, diaphyseal osteitis of the humerus caused by Rhodococcus equi and subsequent medical and surgical management is described.     

8味中草药水提物对马红球菌的体外抑菌和杀菌效果研究

[目的] 筛选对马红球菌（Rhodococcus equi,R. equi）具有抑菌和杀菌效果的中草药。[方法] 选择黄连、黄芩、大青叶、鱼腥草、黄柏、连翘、金银花及板蓝根共8味中草药制备单味水提物,采用微量肉汤稀释法及平板涂布法测定中草药水提物对R. equi参考菌株103S及临床分离株的最小抑菌浓度和最小杀菌浓度。[结果] 不同中草药水提物对R. equi的抑菌及杀菌效果不同,其中,黄连、黄柏和连翘单独用药杀菌及抑菌效果显著（P<0.05）强于其他中草药水提物;黄连、黄柏和连翘不同组合联合用药对R. equi的抑菌及杀菌效果均优于单独用药,其中,“黄连+连翘”联用后药效呈相加作用。[结论] 黄连等中草药对R. equi表现出抑菌及杀菌效果,且联合用药效果优于单独用药,提示这些中草药制剂有望作为抗R. equi乃至其他耐药病原微生物感染的有效治疗药物。     

堆肥臭味物质——粪臭素高效降解菌Rp3的分离和鉴定

为获得粪臭素高效降解菌株,采用摇瓶富集培养和平板划线方法进行降解菌分离,通过感官法和趋化反应初步判定菌株的降解效果,利用高效液相色谱测定菌株对粪臭素的降解率,采用16S rRNA基因序列分析和Biolog鉴定系统对降解菌株进行初步鉴定。结果表明：从羊粪堆肥下土壤分离出的菌株Rp3对粪臭素具有趋化性;菌株Rp3对粪臭素的降解时间随粪臭素浓度的升高而延长。当粪臭素浓度为50 mg·L^-1时,28℃培养24 h,菌株Rp3对粪臭素的降解率达100%;当粪臭素浓度提高到100 mg·L^-1时,培养48 h降解率达到98.4%。菌株Rp3生长适宜pH为7~8;具有较强的耐盐性,在0~10%盐度下,菌株能生长正常。根据其形态特征、16S rRNA基因序列同源性分析和Biolog鉴定系统结果,将该降解菌鉴定为嗜吡啶红球菌Rhodococcus pyridinivorans。上述结果表明：菌株Rp3可以高效降解堆肥臭味物质粪臭素,为堆肥臭味物质的降解提供了新的微生物资源。     

苯酚降解菌DF51的分离鉴定，降解特性及其固定化的研究

从太原市郊苯酚污染的土样中分离到一株能以苯酚、苯甲酸、萘、联苯和苯并噻吩为唯一碳源和能源生长,并且具有同时分解单环和双环芳香类物质能力的菌株,经生理生化和16S rDNA基因序列分析鉴定为红球菌DF51(Rhodococcus sp. DF51). 在本实验条件下,菌株DF51能够有效降解浓度范围为100-800mg L-1的苯酚,该菌代谢苯酚主要是通过邻苯二酚1, 2-双加氧酶催化开环途径进行,同时辅以邻苯二酚2, 3-双加氧酶催化开环,表明菌株DF51兼有混浊红球菌(Rhodoccocus opacus R7)和红球菌PNAN5(Rhodoccocus sp. strain DF51)降解苯酚的途径. 菌株DF51固定化实验表明,该菌的固定化细胞具有降解苯酚的潜在应用价值.